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Possible Duplicate:
Windows XP and RAM 3.5GB+

I have a Dell desktop that had 2GB of Ram in it, but XP's control panel -> system setting said only 1.75 GB. (This is 32 bit XP.)

I then installed another 2 GB, and now XP says I'm at 3.23 GB. I'm sure my graphics card is using shared memory and that might explain some of it, but where can I check that setting to make sure?

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marked as duplicate by Molly, Phoshi, John T, BinaryMisfit Nov 27 '09 at 22:16

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

duplicate? triplicate? probably more :) – Molly7244 Nov 27 '09 at 19:54

It's not a setting you can change, really. Your BIOS, video card, and other hardware need to map their own memory onto the system's address space.

See this post for a simple explanation of what's happening.

You can run the System Information utility to verify that the computer sees the physical RAM; the metric you're interested in is "Total Physical Memory".

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Thank you. According to the utility I have 4GB of physical RAM, which is what I wanted to check-- that I seated both chips correctly. My intel integrated graphics is using 384 MB according to the utility, so that leaves 500MB unaccounted for; most likely divvied up among various drivers and whatnot. – Jim Bancroft Nov 27 '09 at 20:09
i'm afraid you calculation is wrong, 3.25 GB is all what is available to Windows 32-bit (due to the limitations of the x86 hardware architecture), your Intel GMA, "various drivers and whatnot" will then take from this whatever it takes to handle your current applications (dynamically shared video memory). – Molly7244 Nov 27 '09 at 20:29
Hi Molly-- so the GMA and other hardware also use the 3.25 GB along with me? If so, what uses (or can use) the remaining 800 MB? I hadn't heard of x86 only being able to address 3.25 GB-- I thought it could address the entire 4GB, or just about. – Jim Bancroft Nov 27 '09 at 21:39

32-bit Windows XP can only address up to a maximum of ~3.5 GB of RAM. The other 256MB or so is probably shared with your integrated graphics card.

You need a 64-bit operating system to use 4GB or more of RAM. Windows XP 64-bit is not recommended because few companies have drivers that support 64-bit Windows XP. Most start at Windows Vista 64 at least.

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this is only valid if the video memory is fixed in the BIOS and not dynamically shared (which is standard today). – Molly7244 Nov 27 '09 at 20:32

Here's what's happening: Windows takes up some of your RAM, and that is not Included. Furthermore, You can't actually use all 4 GB with 32 bit Windows XP, because it only supports 3.5 GB of memory. You could buy Windows XP 64 bit, but I do not recommend it- it has compatibility issues. Your best bet is to relax and deal with it. You will find that most computers have this "problem".

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